This research is directed toward human need for long lasting fixation of synthetic materials to living tissue. The specific objective of this project is to develop basic information on how mechanical and geometric properties (criteria) of solid metal-porous structures contribute to the mechanical compatibility of an implant-bone attachment system. Variation in physical and geometric properties of porous metals such as elastic modulus, pore characteristics, and size and shape of the porous metal annulus in the attachment zone will be used to optimize transmission of mechanical loads in a solid metal- porous metal- bone system. Macro and micro properties of bone will be studied to provide input data for the bone-metal attachment analysis. Fabrication processes for advanced porous metal structures with controlled modulus and pore geometry will be developed. Materials produced will be fully characterized by appropriate material science techniques and by biological evaluations before and after implantation which was sufficient to give fully calcified tissue ingrowth. Data from material and histological post-mortem testing will be compared in detail and used to optimize the mechanical compatibility of the bone-metal system.